Abstract: Disclosed are marking materials containing retroreflective fillers and processes for the use thereof. In one embodiment, images containing retroreflective fillers are generated on paper by any suitable means, such as electrostatic imaging and development with either dry or liquid developers, ink jet printing, strip-out development processes, or the like, and the images thus generated are used to control a document reproduction system. In another embodiment, images containing retroreflective fillers are generated on a movable part in an imaging apparatus, such as an imaging member, an intermediate transfer member, or the like, by any suitable means, and the images thus generated are used to impart information regarding the relative position of the movable part with respect to the copier or printer containing the movable part.